Question: William ate 3 slices of pie. Luis ate 5 slices. If William ate $\dfrac{3}{12}$ of the pie, what fraction of the pie was eaten?
Answer: If 3 slices represent $\dfrac{3}{12}$ of the pie, there must have been a total of 12 slices. $\text{fraction of pie eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ They ate ${8}$ out of $12$ slices. They ate $\dfrac{8}{12}$ of the pie.